There’s an optimal time to do just about everything, says The Power of When author Michael Breus, Ph.D. The key is to plan around your unique circadian rhythm. These tricks work for almost everyone.

8 A.M.: Hit The Gym

Starting the day with an endorphin rush boosts your mood—and concentration. “Exercise decreases distraction and brings you into the moment,” Breus says. “Then, once you stop, your brain can think again” with clarity.

10 A.M.: Make Big Decisions

As the day wears on, decision fatigue sets in, which is when we start to pick easy options over smart ones. Face your toughest choices in the morning, and if a dilemma presents itself at 6 p.m., get a second opinion.

1 P.M.: Brainstorm

“Creativity peaks when focus is low,” says Breus. “So brainstorming can come from distraction.” If you’re hoping for a lightbulb moment, jot down ideas in the early afternoon, when cortisol, body temperature and alertness dip.

“People are happier toward the end of the day and the week,” says Breus, so make big requests on Thursday or Friday afternoons. Don’t kill the happy hour vibe, though: “Ask at least one hour before the end of the day.”